krypton (krĭp`tŏn) [Gr.,=hidden], gaseous chemical element; symbol Kr; at. no. 36; at. wt. 83.80; m.p. −156.6°C;; b.p. −152.3°C;; density 3.73 grams per liter at STP STP or standard temperature and pressure, standard conditions for measurement of the properties of matter. The standard temperature is the freezing point of pure water, 0°C; or 273.15°K;.
..... Click the link for more information. ; valence usually 0. Krypton is a colorless, odorless, tasteless gas. It is one of the so-called inert gases inert gas or noble gas, any of the elements in Group 18 of the periodic table . In order of increasing atomic number they are: helium , neon , argon , krypton , xenon , and radon .
..... Click the link for more information. found in Group 18 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the
..... Click the link for more information. . It is a rare gas present in air at a concentration of about one part per million. Naturally occurring krypton is a mixture of six stable isotopes. It is produced commercially by fractional distillation of liquid air. Krypton is used to fill electric lamp bulbs and various electronic devices. Fluorescent lamps are filled with a mixture of krypton and argon. Krypton is also used in tungsten-filament photographic projection lamps and in very high-powered electric arc lights used at airports. A mixture of stable and unstable isotopes of krypton is produced by slow neutron fission of uranium in nuclear reactors. Krypton-85 (half-life about 10 years) is the most stable of the 17 radioactive isotopes known; it makes up about 5% by volume of the krypton produced in the nuclear reactor. It is used to detect leaks in sealed containers, to excite phosphors in light sources with no external source of energy, and in medicine to detect abnormal heart openings. Although krypton does not generally form chemical compounds in the normal sense, gram quantities of krypton difluoride have been prepared and several other compounds have been reported. Krypton has characteristic green and orange lines in its spectrum. In 1960 the meter was defined by international agreement as exactly 1,650,763.73 times the wavelength (in a vacuum) of the orange-red line in the emission spectrum of krypton-86 (see weights and measures weights and measures, units and standards for expressing the amount of some quantity, such as length, capacity, or weight; the science of measurement standards and methods is known as metrology.
..... Click the link for more information. ). Krypton was discovered in 1898 by William Ramsay Ramsay, Sir William, 1852–1916, Scottish chemist. He was professor of chemistry at University College, Bristol (1880–87), and at University College, London (1887–1912).
..... Click the link for more information. and W. M. Travers in residue from the evaporation of a sample of liquid air from which oxygen and nitrogen had been removed.

krypton

Chemical element, chemical symbol Kr, atomic number 36. One of the noble gases, it is colourless, odourless, tasteless, and almost totally inert, combining only with fluorine under very rigourous conditions. Krypton occurs in trace amounts in the atmosphere and in rocks and is obtained by fractional distillation of liquefied air. It is used in luminescent tubes, flash lamps, incandescent light bulbs, lasers, and tracer studies.

KRYPTON - A frame language.

["An Essential Hybrid Reasoning System: Knowledge and Symbol Level Accounts of KRYPTON", R.J. Brachman et al, Proc IJCAI-85, 1985].

krypton (redirected from Krypton (element))

krypton

krypton
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